In recent years, there has been a great deal of interest in the development of alternative energy sources, or energy carriers, such as hydrogen. Automobiles and other vehicles that use hydrogen as a fuel source have been developed, but methods for refueling these vehicles that can compete with gasoline fueling stations on scale or cost have not yet been developed. Gasoline fueling stations are very simple and typically only consist of tanks for storing the gasoline and one or more pumps. The options that have been developed for hydrogen fueling to date are expensive, too large and require excessive maintenance.
One option that has been developed provides for storage of gaseous hydrogen at the fueling station and one or more large compressors that are used to raise the pressure of the hydrogen to the pressure required for fueling, typically from 300 to 700 bar.
This option has a large footprint due to the size and design of the compressor system as well as high energy usage.
Another option that has been developed provides for storage of liquid hydrogen at the fueling station. The liquid hydrogen is pumped by a cryopump to a higher pressure and then it is evaporated to gaseous hydrogen that is used for fueling. Both of these options and the others known to those of ordinary skill in the art require mechanical compression or pumping to raise the pressure of the hydrogen for use in fueling vehicles.
To provide a suitable hydrogen dispensing system, the system must be much simpler, cheaper and require less space. In addition, the maintenance requirements and energy use must be reduced to make hydrogen fueling stations a viable alternative to gasoline stations.